U.S. patent application number 09/932226 was filed with the patent office on 2002-06-13 for mobile crane.
Invention is credited to Frommelt, Uwe, Willim, Hans-Dieter.
Application Number | 20020070186 09/932226 |
Document ID | / |
Family ID | 7945334 |
Filed Date | 2002-06-13 |
United States Patent
Application |
20020070186 |
Kind Code |
A1 |
Frommelt, Uwe ; et
al. |
June 13, 2002 |
Mobile crane
Abstract
A mobile crane has a rotating deck supported at an undercarriage
at which a main boom and a derrick counter-boom are supported. A
ballast weight is arranged at the arm of the rotating deck
projecting in the direction of the counter-boom. The ballast weight
is suspended at the counter-boom and can be raised from the
rotating deck via a hoist rope in order to allow a swivelling of
the unloaded crane without the counter-ballast having to be carried
by a carriage following the swivel movement. The counter-boom is
provided with luffing devices by which it can be slanted such that
the ballast weight can approach the luffing axis of the
counter-boom by so much that the overall center of gravity of the
superstructure with the boom, counter-boom and set-ups lies inside
a circle which maintains a safety distance to the tilting edges of
the stabilizer base of the crane.
Inventors: |
Frommelt, Uwe; (Ehingen,
DE) ; Willim, Hans-Dieter; (Ulm, DE) |
Correspondence
Address: |
Rocco S. Barrese, Esq.
DILWORTH & BARRESE, LLP
333 Earle Ovington Blvd.
Uniondale
NY
11553
US
|
Family ID: |
7945334 |
Appl. No.: |
09/932226 |
Filed: |
August 17, 2001 |
Current U.S.
Class: |
212/196 |
Current CPC
Class: |
B66C 23/74 20130101 |
Class at
Publication: |
212/196 |
International
Class: |
B66C 023/76 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 18, 2000 |
DE |
200 14 268.2 |
Claims
1. A mobile crane, comprising a rotating deck supported at the
undercarriage preferably provided with crawlers, at which a main
boom and a derrick counter-boom are supported; and comprising a
ballast weight arranged at an arm of the rotating deck projecting
in the direction of the counter-boom, characterised in that the
ballast weight is suspended at the counter-boom and can be raised
from the rotating deck or the ground via a hoist rope; and in that
the counter-boom is provided with luffing devices by which it can
be slanted such that the ballast weight can approach the luffing
axis of the counter-boom by so much that the overall centre of
gravity of the superstructure with the boom, counter-boom and
set-ups lies inside a circle which maintains a safety distance to
the tilting edges of the stabiliser base of the crane.
2. A crane in accordance with claim 1, wherein the safety distance
corresponds to a radius of the circle which is 25% smaller than the
lowest distance of a tilting edge of the stabiliser base to the
axis of rotation of the rotating deck.
3. A crane in accordance with either of claims 1 or 2, wherein the
ballast weight consists of two stacks or towers which enclose the
projecting arm of the rotating deck between them and which are
supported on this via a carrier connecting the towers.
Description
[0001] The invention relates to a mobile crane having a rotating
deck supported at the undercarriage preferably provided with
crawlers, at which a main boom and a derrick counter-boom are
supported, and having a ballast weight arranged at an arm of the
rotating deck projecting in the direction of the counter-boom.
[0002] Known cranes of this kind usually have a counterweight
fixedly fitted to the rotating deck and additionally a derrick
ballast which consists of a ballast weight suspended via ropes at
the counter-boom. If the load weight suspended at the main boom is
missing in such a derrick crane, the derrick ballast must be set
down on the ground to prevent a backward tilt. If a swivelling of
the unloaded derrick crane should be made possible, the ballast
weight must be carried by a carriage so that it can follow a swivel
movement.
[0003] It is the object of the invention to provide a crane of the
kind first mentioned which allows a swivelling of the unloaded
crane without the counter-ballast having to be carried by a
carriage following the swivel movement.
[0004] This object is solved in accordance with the invention in a
crane of the kind first stated by the ballast weight being
suspended at the counter-boom by a hoist rope and by it being able
to be raised off the rotating deck or the ground and by the
counter-boom being provided with luffing devices by which it can be
slanted such that the ballast weight can approach the luffing axis
of the counter-boom by so much that the overall centre of gravity
of the superstructure with the boom, counter-boom and set-ups lies
inside a circle which maintains a safety distance to the tilting
edges of the stabiliser base of the crane.
[0005] In the crane of the invention, the rotating deck ballast is
combined with the derrick ballast to form one single ballast weight
which can be moved towards the axis of rotation of the rotating
deck by so much with an unloaded crane that it can be placed on
this or on a projecting arm connected to this. If required, the
ballast placed on the rotating deck can again be raised via a hoist
rope of the counter-boom and swivelled in the desired manner to
balance the crane after an appropriately present interlock is
released.
[0006] If a sufficiently large rear swivel area is available, a
load with a substantially reduced ballast weight can be lifted with
the main boom, whereby the required transport effort for the
ballast weight is reduced.
[0007] In the event of obstacles in the rear swivel area, the
ballast can be pulled vertically upwards so that obstacles can be
passed over.
[0008] With the crane of the invention, a very large ballast can be
fitted to or set down on the rotating deck which rests on the
rotating deck in normal operation. If, however, the load moment is
high, then the ballast is raised out of its latch at the rotating
deck via a winch in the derrick counter-boom and swivelled so far
to the back until the load moment and the counter-moment are
approximately the same.
[0009] The safety distance appropriately corresponds to a radius of
the circle which is 25% smaller than the lowest distance of a
tilting edge of the stabiliser base to the axis of rotation of the
rotating deck.
[0010] To allow the ballast weight to be set on the rotating deck
and to be raised from this via the hoist winch of the derrick
counter-boom, the ballast weight appropriately consists of two
stacks or towers which enclose the projecting arm of the rotating
deck between them and are supported on this via a carrier
connecting the towers.
[0011] The crane according to the invention can also be operated in
such a manner that the ballast weight is not set on the rotating
deck but is raised from the ground and is suspended in a freely
floating manner.
[0012] An embodiment of the invention is explained in more detail
below with reference to the drawing, in which are shown:
[0013] FIG. 1 a derrick crane in a state in which the counter-boom
is set so steep that via this a ballast weight can be set on the
rotating deck and can be raised from it; and
[0014] FIG. 2 the crane of FIG. 1 in a state in which the
counter-boom is luffed into a position in which the counterweight
has such a large radius from the axis of rotation of the rotating
deck that it can balance a great load suspended at the main
boom.
[0015] A derrick crane is visible from FIGS. 1 and 2 having an
undercarriage 1 which is provided with crawlers. The main boom 3
and the derrick counter-boom 4 are supported in the usual manner at
the rotating deck 2 rotatably supported on the undercarriage 1.
Usual devices are provided for the luffing of the main boom 3 and
the counter-boom 4. The head parts of the main boom 3 and of the
counter-boom 4 are anchored with respect to one another in a usual
manner by an adjustment block 5. The main boom 3, which can consist
in the form shown of a latticed mast or also of a telescopic boom,
is provided in the usual manner with a lower block 7 carrying a
load hook 6. The drive for the hoist rope is of a known type and is
not described in any more detail.
[0016] A hoist rope, at whose lower block a ballast weight 9 is
suspended, runs in a usual manner over return pulleys of the head
part 8 of the counter-boom 4. The ballast weight 9 consists of two
side stacks or towers which are connected to one another in
bridge-like form by a cross member such that the ballast weight 9
can be placed onto an arm 10 of the rotating deck projected
backwards when the counter-booms 4 are slanted, as is visible from
FIG. 1.
[0017] The undercarriage 1 can additionally be supported by
stabilisers (not shown). The ballast weight can be set down within
the stabiliser base of the crane and then taken up by the hoist
block of the counter-boom 4 for the receiving of the ballast
weight.
[0018] The crane is conceived such that the ballast weight 1 can be
swivelled so near to the axis of rotation of the superstructure
when the counter-boom is slanted that the overall centre of gravity
of the superstructure 1 with the boom, counter-boom, ballast weight
and set-ups is located within a circle which still maintains a
safety distance to the tilting edges of the stabiliser base of the
crane.
* * * * *